BFF doesn't want to be in my wedding :/

Long story short, my best friends fiancé called off their wedding at the beginning of the year. Now fast forward and I'm engaged (yay!) but she was super not excited. I decided to talk to her and ask if she'd still like to be a part of my wedding. She said she's not able to because she doesn't think she can handle it. The wedding is about a year away. I am still asking very close friends to be in my wedding party but she's my best friend and I can't help but be really sad that she can't be there for me. Especially since I was (going to be) her maid of honor while I was going through a divorce with my ex. (They were engaged for 3.5 years). Has anyone dealt with this? I'm super bummed and feel like she's going to regret not being a part of it when it comes around.